So far I'm happy with the Quad DE80. And the hi-flow valve, despite the contorted plumbing, has preserved the better flow rate of the DE80. The hi-flow turned out to be the right decision (I was worried about flow friction).
I can run at 1100rpm, but have it at 1300 for margin as the filter gains more backpressure.
Overal all system backpressure is 2x better than the old filter/slide valve combination at max flow rate. Wow!
filter pressure is zero PSI since install.
My only worry is that the filter seems to collect a small amount of air over the course of a week. I manually bleed it off, but this seems wrong.
Also, is there a simple method to estimate GPM based on watts or RPM or both?